简介：AkindofcircularringhighfrequencywidebandunderwateracoustictransducerisdevelopedbyusingtheLowQvalueandbroadbandcharacteristicsofthepiezoelectricitycompositematerial,andthedualmodecouplingisusedtobroadenthebandwidthofthetransducerbydoubleringstackingalongtheaxialdirection.Throughtheoreticalanalysisandsimulationcalculation,thegeometricdimensionsofthesensitivecomponentsaredetermined.Thepiezoelectriccompositeringsareprocessedandthenthestacksensitiveelementcanbemadebystackingtwopiezoelectriccompositeringswiththesameouterdiameteranddifferentthicknessinaxialdirectionbycuttingpiezoelectricceramicsfillingtheflexiblepolymer-coatingelectrode.Finally,thetransducercanbemadebypouringwaterproofsound-permeablelayer.Theperformancesoftransducerhavealsobeentestedinthewaterandthetestresultsshowthattheresonantfrequencyis410kHz,themaximumtransmitvoltageresponseis150dB,the-3dBbandwidthcanreaches60kHz,thehorizontaldirectivity(-5dB)is360°,andtheverticaldirectivity(-3dB)is20°.Itisalsoshownthatthebandwidthofthetransducercanbeenlargedremarkablybyusingthemethodofstackingtwodifferentthicknesspiezoelectriccompositeringsalongtheaxialdirection,andthehorizontalomnidirectionalemissionofacousticwavecanberealized

简介：Radio-frequency（RF）tomographyisanemergingtechnologywhichderivestargetslocationinformationbyanalyzingthechangesofreceivedsignalstrength（RSS）inwirelesslinks.ThispaperpresentsandevaluatesanovelRFtomographysystemwhichiscapableofdetectingandtrackingatime-varyingnumberoftargetsinaclutteredindoorenvironment.ThesystemincorporatesanobservationmodelbasedonRSSattenuationhistogramandamulti-targettracking-by-detectionfilteringapproachbasedonprobabilityhypothesisdensity（PHD）filter.Inaddition,thesequentialMonteCarlomethodisappliedtoimplementthemulti-targetfiltering.Toevaluatethetrackingsystem,theexperimentsinvolvingupto3targetswereperformedwithinanobstructedindoorareaof70m^2.Theexperimentalresultsindicatethattheproposedtrackingsystemiscapableoftrackingatime-varyingnumberoftargets.

简介：Theabsorptionspectrumofthecyclotrime-thylenetrinitramine(RDX)withfourdifferentparticlesizesaremeasuredinthefrequencyrangefrom0.1THzto2.5THzbyusingtheterahertztime-domainspectroscopy(THz-TDS),andthecharacteristicabsorptionpeaksareacquired.Allthesamplesaremeasuredinaloosecondition,whichisveryclosetotherealusingenvironmentoftheRDX.Theresultsshowthatthefourkindsofsampleshavesimilarabsorptionpeaksaroundthefrequencyof0.82THz,1.05THz,1.30THz,1.46THz,1.65THz,and1.95THz.Thesamplewithalargeparticlesizeobtainsmorepeaksthanthesmallone,whilethepeaksobtainedfromthesamplewithasmallsizearemoreprotrudent.Thereasonsforthesedifferencescanbetherefraction,scattering,andattenuationoftheterahertzwavewhenitpassesthroughthecrystalsamples.ThetheoreticalterahertzspectrumofRDXwassimulatedbyusingdensityfunctionalcalculations,inwhich,theBecke&Perdew-Wang’sfunctionalisusedinadoublenumericalpluspolarizationmethod(BP/DNP).Goodagreementsbetweentheexperimentalandcomputedresultsshowthatthethreepeakslocatedinthefrequencyof1.30THz,1.48THz,and1.96THzarecausedrespectivelybythetwistingofthree-nitrogenheterocyclic,thesymmetricaloscillationsofthedoublenitrogroups,andtheoscillationsofasinglenitrogroup.

简介：Anewadaptivecontrolschemeisproposedformultivariablemodelreferenceadaptivecontrol(MRAC)systemsbasedonthenonlinearbacksteppingapproachwithvectorform.Theassumptiononaprioriknowledgeofthehighfrequencygainmatrixinexistingresultsisrelaxedandthenewrequiredconditionforthehighfrequencygainmatrixcanbeeasilycheckedforcertainplantssothattheproposedmethodiswidelyapplicable.Thiscontrolschemeguaranteestheglobalstabilityoftheclosed-loopsystemsandthetrackingerrorcanbearbitrarysmall.Thesimulationresultforanapplicationexampleshowsthevalidityoftheproposednonlinearadaptivescheme.

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简介：Experimentsonsonictransmissionshowthataslabstonecandirectlytransmitpartoftheenergyofawaveexcitedbyknockingorbyatransducerintotheair.Theotherpartofthewaveenergycangeneratethenormalmodeofvibrationontheslabstoneandexcitemeasurableacousticsignalsintheair.Thedominantfrequencyisrelatedtothesizeoftheslabstone.Theseresultsindicatethattheacousticemission(AE)inrockalsodisplayssimilarbehaviorifthesourceisshallow.Itisdemonstratedthatwiththenucleationandpropagationofcracks,thedominantfrequencyoftheradiatedwavewillbelower.Whenthefrequencybecomesverylow,thewavecanbetransmittedthroughtherockintotheairandbereceivedbyamicrophone.Accordingtothetheoryofsimilarityofsize,therewillbelow-frequencywavesbeforestrongearthquakesbecauseofnucleationofcracks,whichcanbereceivedbyspeciallow-frequencytransducersorinfrasonicdetectors.Beforeearthquakes,themechanismofprecursorscouldbeverycomplicated.Theymightbeproducedbyplasticcreeporattributedtoliquidsbutnotbrittlefractureinmostcases.Sotheperiodsoftheproducedwaveswillbelonger.Thisperhapsaccountsforthelackofforeshocksbeforemanystrongearthquakes.

简介：摘要BACKGROUND AND OBJECTIVESPaired associative stimulation (PAS), a combination of transcranial magnetic stimulation (TMS) with peripheral nerve stimulation (PNS), is emerging as a promising tool for alleviation of motor deficits in neurological disorders. The effectiveness and feasibility of PAS protocols are essential for their use in clinical practice. Plasticity induction by conventional PAS can be variable and unstable. Protocols effective in challenging clinical conditions are needed. We have shown previously that PAS employing 50 Hz PNS enhances motor performance in chronic spinal cord injury patients and induces robust motor-evoked potential (MEP) potentiation in healthy subjects. Here we investigated whether the effectiveness of PAS can be further enhanced.METHODSPotentiation of MEPs up to 60 minutes after PAS with PNS frequencies of 25, 50, and 100 Hz was tested in healthy subjects.RESULTSPAS with 100 Hz PNS was more effective than 50 (P＝0.009) and 25 Hz (P＝0.016) protocols. Moreover, when administered for 3 days, PAS with 100 Hz led to significant MEP potentiation on the 3rd day (P＝0.043) even when the TMS target was selected suboptimally (modelling cases where finding an optimal site for TMS is problematic due to a neurological disease)．CONCLUSIONS PAS with 100 Hz PNS is thus effective and feasible for clinical applications.

简介：TheaimofthisstudyistofindtheexperimentalevidencethattheprecursorfrequencyofalloreactiveCTLsisproportionaltothenumberoftheT-cellepitopespecificities.ThenumberofT-cellepitopespecificitieswasmanipulatedbypulsingdifferentnumberofHLA-A2restrictedpeptide(s)ontotheT2cells,whichactedasstimulatingcellstoelicitallo-reactionbyco-culturingwithperipheralbloodlymphocytes(PBLs)ofHLA-A2negativeindividual.TenHLA-A2restrictedpeptides(allwerenormalcellcomponents)weresynthesized,andcellpeptideextractwaspreparedbyfrozenandthawed.T2cellsloadedwithdifferentnumberofpeptide(s)wereco-culturedwithPBLsofanHLA-A2negativeindividual;thelatterwerestainedwithPKH67inadvance.Thentheproliferationwasmonitoredwithflowcytometry,andtheprecursorfrequencyoftheeffectorcellswasanalyzedbytheModFitSoftware.After6dofculture,noproliferationwasobservedinthebulkcultureofPBLalone,andobviousproliferationtookplacewhenPBLsoftheHLA-A2negativewereco-culturedwithT2cellsloadedwithorwithoutloadingpeptide(s).TheprecursorfrequencyofthealloreactiveCTLswas0.052819forco-culturewithT2cellsloadedwithoutpeptide;howeveritwas0.030429forT2cellswithEBV/LMP2Aand0.030528forT2cellsloadedwithasingleautogeneicpeptide,andincreasedupto0.144942forT2cellsloadedwith10autogeneicpeptides;theprecursorfrequencywas0.203649whenco-culturedwithT2cellsloadedwithmiscellaneouspeptidesextractedfromthecytoplasmofT2cells.ThisstudyrevealsthattheprecursorfrequencyofalloreactiveCTLsisproportionaltothenumberofT-cellepitopespecificities,andindependentofthedensityoftheallogeneicHLAClassⅠmolecule.OurfindingssupportthehypothesisthatthealloreactiveTcellpopulationscomprisemiscellaneousTcellclones;eachisspecifictocorrespondingpMHC.ThenovelconstellationofpeptidespresentedbyallogeneicMHCmoleculesmakesthous

简介：ObjectiveToassesstheutilityoflow-andhigh-frequencytympanometryinthediagnosisofmiddleeardysfunctioninChineseinfants.MethodsTympanogramswereobtainedwith226Hz,678Hzand1000Hzprobetonesfrominfantsaged5-25weekswithnormalauditorybrainstemresponses(ABRs)(15infants,30ears)andwithprolongedwaveIlatencies(17infants,20ears),suggestingmiddleeardysfunction,usingaGSITympstarmiddleearanalyzerVersionII.ResultsThesingle-peakedtympanogramwasthemostcharacteristictypeinbothgroupsandseenin25ears(83.3%)inthenormalABRgroupandin18ears(90%)inthedelayedwaveIgroup,respectively.Thepeakpressure,peakcompensatedstaticacousticadmittanceandgradientof226Hztympanometrywereofnosignificantdifferencesbetweenthetwogroups.The678Hztympanogramsofadmittance,susceptanceandconductancedemonstratednon-peak,single-,double-andtri-peakedpatternsinbothgroups.TheagreementbetweenABRsand678Hztympanogramsofadmittance,susceptanceandconductancewere70.0%,58.0%and64.0%(kappa=0.324,0.234and0.118)respectively.For1000Hzprobetone,admittance,susceptanceandconductancetympanogramsshowedsinglepeakedpatternsin28(93.3%),25(83.3%)and26(86.7%)ofthe30normalears.Admittance,susceptanceandconductancetympanogramsusingthe1000Hzprobetonewereflatin15(75%),17(85%)and13(65%)oftheearsininfantswithprolongedwaveIlatencies.For1000Hzadmittance,susceptanceandconductanceTympanograms,theagreementbetweentympanometryandABRresultswere90.0%,92.0%and86.0%withkappaat0.783,0.831and0.690,respectively.Conclusion1000Hzprobetonetympanometryisapromisingmiddleearfunctiontestforinfantsof1-6monthsage,while226Hzand678Hzprobetonesarelessefficientindetectingmiddleeardysfunctionininfants.

简介：放精确的GPS被GPS搬运人阶段观察的各种各样的错误来源，和传统的联合影响有他们的自己的限制例如宽小巷，狭窄小巷并且ionospheric免费的联合。获得最佳的放精确，一个新线性组合方法通过放的精确的GPS多频率搬运人阶段联合方程，和影响的变化协变性(VCV)被探讨与变化误差传播定律推出的观察错误被分析。为与一仅仅搬运人阶段联合放的高精确，最佳的联合方法被基线分辨率的一个例子与60km长度推出并且进一步验证了。结果显示这个方法最简单，并且放的精确是最好。因此，在各种各样的远处为不同精确要求放，快为长基线是有用的。

简介：Thispaperproposesadecentralizedoutputfeedbackcontrolschemeappliedtotwo-areainterconnectedpowersystem.ThecontrollersynthesisproblemisformulatedasthescaledH∞controlproblemandanewLMI-basedalgorithmisproposedtocomputethedecentralizedcontroller.TheproposedcontrollerprovidesrobustnesswithregardtoparametricuncertaintiesandalsoattenuatesboundedexogenousdisturbancesinthesenseofL2-gain.Simulationresultsclearlyshowtheeffectivenessofdevelopeddecentralizedoutputfeedbackcontrolscheme.

简介：Anewisolatorcomposedofasteelropespringandamagneto-rheological(MR)damperwasdesignedandastudyonlow-frequencymechanicalcharacteristicsofMRdampersinisolatorswascarriedout.ItusedthecharacteristicsoftheMRdamper,suchasfastresponse,controllabledamping,smallenergyconsumption,widedynamicscope,andgreatadaptation.TherelationshipsbetweenMRdampingforcesandinfluencingfactorswereanalyzedbasedonexperimentaldata.Theresultsshowthatdampingforceisnotonlyrelatedtostructuraldimensions,butalsocloselyrelatedtocontrollablecurrentandvibrationfrequency.Finally,theempiricalformulafordampingforceswascorrected,andtherelationshipbetweencorrectioncoefficientsandfactorsanalyzed.

简介：InthedigitalsynthesisofwidebandperiodicsignalsusinganArbitraryWaveformGen-erator(AWG),thefrequencyresolutionandspectralcomplexityofthesynthesizedsignalsarecom-monlylimitedbythememorycapacityandclockfrequencyoftheAWG.Thispaperproposesanovelsequentialaddressingschemeandthenpresentsseveralsequencestoimprovethefrequencyresolutionofthesynthesizedperiodicsignalswithoutchangingtheirspectralenvelopesandbasictime-domaincharacteristicsundertheconditionofafixedmemorycapacityandafixedclockfre-quency.ThemainideaoftheschemeisusingtheaddressgeneratorinanAWGtoprogramandproduceaddressestoreadfixedwaveformdatainvariableorder,andthustogeneratewaveformsofvariousperiodsandprofiles.Theschemeisappliedinsimulatingsignalscenariosformilitarycom-municationcountermeasureexperiments,andachieveshighperformance.

简介：Theoreticalconsiderationwasproposedforthefrequencyresponseofaseriespiezoelectricsensortothepropertiesofliquidandverifiedexperimentally.Thiskindofsensorhassensitiveandselectivefrequencyresponsetothepermittivityandspecificconductivityofsolutionwithexcellentstability,andwasappliedtothedeterminationofmicro-contentofwaterinorganicsolvents.Thedetectionlimitis0.01g/Lindioxane.

简介：Withtheincreasingpenetrationofrenewableenergysourceswithawiderangeofoperatingconditionscausingpowersystemuncertainties,conventionalcontrollersareincapableofprovidingproperperformancetokeepthesystemstable.However,controllableordispatchableloadssuchaselectricvehicles(EVs)andheatpumps(HPs)canbeutilizedforsupplementaryfrequencycontrol.Thispapershowstheabilityofplug-inhybridEVs,HPs,andbatteries(BTs)tocontributeinthefrequencycontrolofanisolatedpowersystem.Moreover,weproposeanewonlineintelligentapproachbyusingacoefficientdiagrammethod(CDM)toenhancethesystemperformanceandrobustnessagainstuncertainties.TheperformanceoftheproposedintelligentCDMcontrolhasbeencomparedwiththeproportional-integral(PI)controllerandthesuperiorityoftheproposedschemehasbeenverifiedinMatlab/Simulinkprograms.

简介：这篇论文的目的是为通过一系列试验性的研究和数字计算加热过程的线调查高周波的正式就职热的可行性。结果证明感应的加热的加热温度遇见钢板弯曲，和感应的加热加热的一个钢盘子的变丑的要求当火焰加热，能完成一样的效果。同时，板的动人的感应的加热的有限元素模型被开发，并且剩余种类的比较回答，在这些二种加热之间的横向的收缩证明那大类似被完成了。

简介：Time-frequencyanalysisiscombinedwitharrayprocessingtodevelopadirectionofarrival(DOA)estimationmethod.Thearraydatamodelisconstructedintime-frequencydomainbycrosstime-frequencydistributionbetweentheoutputofareferencesensorandthoseoftwosymmetricsub-arrays.Accordinglyasubspacemethodispresentedbasedontheaverageoftwosub-arrays'time-frequencydatavectormodelinsteadoftheconventionalarraymodel,toestimateDOAsofmultiplesignals.Becausethearraydataisprocessedbothinspatialdomainand2-Dtime-frequencydomain,theproposedmethodhasanabilitytoselectthesignalofinteresting,andissuitablefornon-stationarysignal.Additionally,themethodisrobusttonoiseandholdsanadvantageoflowcomputationalload.Simulationsareconductedtoverifytheefficiencyofthemethodandcomparisionismadewithothermethods.

简介：在这份报纸，用在土中的轴承和频率大小的联合集合的一个新被动修改重申的扩大Kalman过滤器(MIEKF)集中了惯性(ECI)坐标被建议。MIEKF的一个新测量更改方程被修改高斯牛顿重复的客观功能导出。一个新获得方程和重复结束标准被使用最大的可能性的估计的性质获得。接近的秒顺序线性化州的繁殖方程，州的转移的Jacobian矩阵和测量方程在卫星被导出二身体的运动。MIEKF，重申的扩大Kalman过滤器(IEKF)和扩大Kalman过滤器(EKF)的追踪的表演从STK8.1通过模仿的数据经由蒙特卡罗模拟被比较。模拟结果显示建议MIEKF是可能的消极地由一颗高地球轨道卫星追踪低地球通报轨道卫星，并且更高让比IEKF和EKF追踪精确。

简介：Aone-dimensionalequivalentlinearmethod(EQL)iswidelyusedinestimatingseismicgroundresponse.Forthismethod,theshearmodulusanddampingratioofinelasticsoilaresupposedtobefrequencyindependent.However,historicalearthquakerecordsandlaboratorytestresultsindicatethatnonlinearsoilbehaviorisfrequencydependent.Severalfrequency-dependentequivalentlinearmethods(FDEQL)relatedtotheFourieramplitudeofshearstraintimehistoryhavebeendevelopedtotakeintoaccountthefrequency-dependentsoilbehavior.Furthermore,theshearstrainthresholdplaysanimportantroleinsoilbehavior.Forshearstrainsbelowtheelasticshearstrainthreshold,soilbehavesessentiallyasalinearelasticmaterial.Toconsidertheeffectofelastic-shear-strain-thresholdandfrequency-dependentsoilbehavioronwavepropagation,theshear-strain-threshold-andfrequency-dependentequivalentlinearmethod(TFDEQL)isproposed.AseriesofanalysesisimplementedforEQL,FDEQL,andTFDEQLmethods.Resultsshowthatelastic-shear-strain-thresholdandfrequency-dependentsoilbehaviorplaysagreatinfluenceonthecomputedsiteresponse,especiallyforthehighfrequencyband.Also,theeffectofelastic-strain-thresholdandfrequency-dependentsoilbehavioronthesiteresponseisanalyzedfromrelativelyweaktostronginputmotion,andresultsshowthattheeffectismorepronouncedasinputmotiongoesfromweaktostrong.

简介：动态、数字的方法被用来热强迫讨论大气的反应到SST。结果表演为行星的规模系统，热强迫能快速激动的站的SST稳定的大气的平衡状态回答，它被明显的大规模电视连接摆动在东方西方和南方北方方向描绘。为摘要的规模系统，SST热强迫主要使大气的低频率的摆动激动。在SST之间的某基本关系和动态过程热强迫和大气的反应模式被揭示，一些新观点被介绍。